Double Harvest Research Articles

Convolutional Neural Network-Based Estimation of Nitrogen Content in Regenerating Rice Leaves

Regenerated rice, characterized by single planting and double harvesting, saves labor and costs, significantly contributing to global food security. Hyperspectral imaging technology, which integrates image and spectral data, provides comprehensive, non-destructive, and pollution-free vegetation canopy analysis, making it highly effective for crop nutrient diagnosis. In this study, we selected two varieties of regenerated rice for field trials. Hyperspectral images were captured during key growth stages (flush, grouting, and ripening) of both the first and regenerated seasons. Utilizing a two-dimensional convolutional neural network (2D-CNN) as a deep feature extractor and a fully connected layer for nitrogen content prediction, we developed a robust model suitable for estimating nitrogen content in regenerated rice. The experimental results demonstrate that our method achieves a mean squared error (MSE) of 0.0008, significantly outperforming the back-propagation (BP) network and multiple linear regression by reducing the MSE by 0.0151 and 0.0247, respectively. It also surpasses the one-dimensional convolutional neural network (1D-CNN) by 0.003. This approach ensures accurate nitrogen content prediction throughout the growth cycle of regenerated rice, aiding in yield and economic benefit enhancement.

Maize–soybean relay cropping increases soybean yield synergistically by extending the post-anthesis leaf stay-green period and accelerating grain filling

Relay cropping of Poaceae and Fabaceae promotes high yield and land-use efficiency by allowing a double harvest. However, it is difficult to increase yield synergistically because of the reduced photosynthetic abilities of legume leaves under the shade of graminoids. Leaf photosynthetic capacity in relay cropping systems is associated with ecological niche differentiation and photosynthetic compensation after restoration of normal light. We conducted a field experiment in southwest China in 2020–2021 to evaluate the effects of three cropping patterns: maize–soybean relay cropping (IMS), monoculture maize (MM), and monoculture soybean (SS), and N application levels: no N application (NN:0 kg N ha−1), reduced N (RN: 180 kg N ha−1), and conventional N (CN: 240 kg N ha−1). Compared to monocropping, relay cropping increased the stay-green traits of maize and soybean by 13% and 89%, respectively. Relay cropping prolonged the leaf stay-green duration in the maize and soybean lag phase by almost 4 and 8 days, respectively. Relay cropping maize (IM) increased the leaf area index (LAI) by 79.4% to 88.5% under NN and 55.5% to 148% under RN. Relay cropping soybean (IS) increased the LAI from 115% to 437% at days 40 to 50 after anthesis. IM increased yield by 65.6%. IS increased yield by 9.7%. HI and system yield were at their highest values under RN. In the relay cropping system, reduced N application extended green leaf duration, increased photosynthesis inside the canopy at multiple levels, ultimately increases soybean yield synergistically.

Agronomic Practices in Lemon Balm Production under Temperate Climate Conditions: Raw Material Yield and Active Substances Content

The cultivation of lemon balm (Melissa officinalis L.) is necessary for pharmaceutical and cosmetic production. The aim of our work was to investigate the effect of the plant density as well as the harvesting method on the yield and quality characteristics of M. officinalis, which is used as a source of polyphenols and essential oil in the pharmaceutical, food, and cosmetic industries. The field experiment was carried out in two growing seasons (2019 and 2020). The experiment was set up as a 2-factor experiment; the factors studied were the plant spacing (30 × 30 cm or 40 × 40 cm) and the harvesting method (single harvesting or double harvesting). The lemon balm herb was cut twice (in mid-July and early September) or once (in early September) depending on the combination. The air-dried leaves were subjected to laboratory tests to determine the essential oil, total tannin, and total flavonoid contents. The yield of lemon balm in the individual years in the study depended more on the harvesting method than on the plant density. The essential oil content was 0.25–0.38% depending on the plant density. Considering the yields of the fresh and air-dried herb and leaves, essential oil yield and oil, and tannin and flavonoid contents, a higher plant density (40 × 40 cm) is a better agronomic option than a lower density (30 × 30 cm). Harvesting the herb twice proved to be more efficient in terms of quantity and quality than a single harvest.

Correlation between Changes in Soil Properties and Microbial Diversity Driven by Different Management in Artificial Chinese Fir (Cunninghamia lanceolata (Lamb.) Hook.) Plantations

Successive planting is the main pattern for cultivating Chinese fir (Cunninghamia. lanceolata (Lamb.) Hook.). However, the influence of this management has not been totally investigated, especially with respect to the changes in the soil microbial community and the relationship to soil properties. This study investigated the physical and chemical properties of the soil, its enzyme activities, and its microbial diversity in three adjoining plantations managed with different successive planting models (long-term continuous growth without harvest, M1; single harvest cutting followed by the construction of a pure plantation, M2; and double harvest cutting followed by the construction of a mixed plantation, M3) to evaluate the impact of these forest management practices. In most soil layers, M1 was observed to have significantly higher content of Na and Al ions, as well as more polyphenol oxidase (PPO) activity, and M2 had a significantly higher field moisture capacity (FMC) and content of Mg ions, while M3 had significantly higher urease (URE) activity. Changes in the totals of N (TN) and C (TC), alongside the availability of P (AP), C/P, N/P, URE, sucrose (SUC), and PPO values, correlated significantly with bacterial diversity, whereas the dynamics of total K (TK), Na, C/P, N/P, and PPO levels were significantly related to fungal diversity. Among the models, soil bacterial genera, including Burkholderia–Caballeronia–Paraburkholderia, Acidothermus, and Paenibacillus, were mostly affected by TN, TC, AP, organic matter (OM), C/N, C/P, N/P, SUC, and the performance of URE. The distribution of fungal genera in different models showed significant differences. Talaromyces, Trichoderma, and Aspergillus were relatively abundant in M1, while Umbelopsis and Saitozyma exhibited more adaptation in M3. These results illustrated better soil properties and higher abundance of microbial diversity in M1 and M3, and furthermore, demonstrated the strategic benefit of both prolonging the rotation period and of creating mixed artificial plantations to maintain diversity. This study improves the understanding of the impact of a successive planting strategy in C. lanceolata plantation sustainability.

Ralstonia solanacearum: a potential target by organic ecology in ginger (Zingiber officinale Roscoe) production

Extensive cultivation of ginger for years caused ecological environment worse off and ginger productivity decrease due to wilt diseases, which also happens in nearly all crops in continuous cropping, especially in Ralstonia solanacearum caused wilt farmlands. In the present work, based on analysis of Ralstonia solanacearum species complex (RSSC) host plant phylogeny and RSSC control factors, an organic ecological method to combat the wilt is proposed that is expected to guarantee continuous cropping of ginger (Zingiber officinale Rosc.) achieving double harvest in economy and environment.

Enhanced Cd Phytoextraction by Solanum nigrum L. from Contaminated Soils Combined with the Application of N Fertilizers and Double Harvests.

It is very important to increase phytoremediation efficiency in practice in suitable climatic conditions for plant growth through multiple harvests. Solanum nigrum L. is a Cd hyperaccumulator. In the present experiment, after applying different types of N fertilizers (NH4HCO3, NH4Cl, (NH4)2SO4, CH4N2O), root and shoot biomasses and Cd phytoextraction efficiency of S. nigrum effectively improved (p < 0.05). Shoot biomasses of S. nigrum harvested at the first florescence stage plus the amounts at the second florescence stage were higher than those harvested at the maturation stage, which indicates that S. nigrum Cd phytoaccumulation efficiency was higher in the former compared to the latter as there was no clear change in Cd concentration (p < 0.05). The pH value and extractable Cd contents showed no changes, regardless of whether N fertilizer was added or not at different growth stages. In addition, after N fertilizer was applied, H2O2 and malondialdehyde (MDA) contents in S. nigrum in vivo were lower compared to those that had not received N addition (CK); similarly, the concentration of proline was decreased as well (p < 0.05). The activity of the antioxidant enzyme catalase (CAT), harvested at different growth periods after four types of N fertilizer applications, obviously decreased in S. nigrum shoots, while peroxidase (POD) and superoxide dismutase) (SOD) activities increased (p < 0.05). Our study demonstrated that (NH4)2SO4 treatment exerted the most positive effect and CH4N2O the second most positive effect on S. nigrum Cd phytoremediation efficiency in double harvests at florescence stages, and the growth conditions were better than others.

Construction of continuous heat conductive channel, a double harvest strategy to enhance thermal conductance and bending strength of C/SiC composites

The development of efficient and quick method to prepare structure-function integrative C/SiC composites is always a major challenge in this field. Herein, the thermal conductivity and bending strength of C/SiC composites were enhanced simultaneously via continuous high heat conductive channels constructed by continuous wave laser machining and pitch-based high thermal conductivity carbon fiber in thickness direction. Results revealed that the thermal conductivity of the modified C/SiC composites is three times higher than that of referential C/SiC composites due to its highly ordered heat conducive channel in the thickness direction. Importantly, the bending strength of modified C/SiC composites increased to 457 MPa. To better understand the enhance mechanism, the micro-structure for both the composites and heat conductive channel was systematically analyzed. The results demonstrated that the rivet effect of heat conductive channel and the formed two phases structure on the fibers dispersed partial of load and finally enhanced the property of the composites. In a word, this method holds a nice applicable future in constructing structure-function integrative C/SiC composites.

Biomass yield and quality of perennial herbaceous crops in a double harvest in a continental environment

Perennial herbaceous crops (PHC) diversity requires the proper selection of genotypes with high biomass production. These crops can be harvested at different stages of the vegetation period. The objective of the study was to determine the yield and biomass quality of seven PHC genotypes, including three dicotyledon plants (Helianthus tuberosus L., Helianthus salicifolius A. Dietr, Silphium perfoliatum L.) and four monocot plants (Miscanthus × giganteus J.M. Greef & M. Deuter, M. sinensis ((Thunb.) Andersson), M. sacchariflorus ((Maxim.) Hack.), Spartina pectinata Bosc ex Link) during double harvest (June and October) in three vegetation periods. The highest yield in the first harvest (June) was obtained from S. perfoliatum (7.7 Mg ha−1 y−1 d.m.). However, in the second harvest (October), the yield of this genotype was not so high, and the total yield from two harvests (June + October) was 11.6 Mg ha−1 y−1 d.m. The highest yield from two harvests was obtained from S. pectinata (13.5 Mg ha−1 y−1 d.m.). The yields of PHC harvested twice in one growing period, obtained in the third year of the study, were lower compared with the yields obtained in the first and second years. It was shown that the moisture and nitrogen contents in biomass obtained in the first harvest were higher in all genotypes compared with the second harvest. It was also found that dicotyledon plants contained more ash and lignin than grasses. However, the grasses had higher contents of cellulose and hemicelluloses. The above information is important to customers and end-users of PHC.

Phytoremediation of cadmium contaminated alkaline soil using the ornamental hyperaccumulator Mirabilis jalapa L. enhanced by double harvesting: a field study.

Ornamental hyperaccumulators are considered ideal plants for phytoremediation of cadmium (Cd)-contaminated soils because of their high accumulation capacity and minimal potential to enter the food chain. Aiming to estimate the phytoremediation efficiency and explore the influence of double harvesting, a filed study was carried out in Cd-contaminated alkaline soil using the ornamental hyperaccumulator Mirabilis jalapa L. Seeds of M. jalapa were sawn with spacing in rows of 15cm and in lines of 20cm on April 20th. Three treatments with different harvesting strategies were arranged: all plants were harvested once on September 10th (marked with H0), and the plants were harvested on July 20th for the first time at a height above ground of 50cm and 30cm (marked with H1 and H2, respectively), and then, they were harvested on September 10th for the second time. The plant samples were digested with a mixture of HNO3 and HClO4 and determined using ICP-MS. The results showed that the total biomass of the shoots increased from 505.81 ± 8.29g/m2 in the H0 treatment to 849.72 ± 59.73 and 933.14 ± 96.12g/m2 in the H1 and H2 treatments, respectively, while the total Cd accumulation in the shoots was 42.32 ± 4.44, 52.99 ± 7.32, and 56.30 ± 6.95g/ha in the H0, H1, and H2 treatments, respectively. Phytoremediation efficiencies increased by at least 20% after the application of double harvesting. However, double harvesting also decreased the translocation and bioconcentration factors with a reduction of 30-55% because the Cd concentration in the shoots was low at the first harvest. Our results suggested that double harvesting is a powerful method to improve phytoremediation efficiency with low costs and minimal risk, and other technologies should be applied together to address the accumulation and translocation of Cd.

Sorghum cultivation of the ratoon system for increased yields in dry land

Planting sorghum twice a year on dry land is constrained by the short duration of rainfall, so it requires technology to increase yields with the ratoon cropping system. The research was carried out in Agricultural Technology Research and Assessment Installation of Bajeng, Gowa, South Sulawesi from March to October 2019. The superior genotypes of sorghum were planted on marginal land as the main crop with a spacing of 75 cm x 20 cm (66,666 plants/ha). The ratoon plant used a split-split plot design. The main plot consisted of two mulches: M1=no mulch + 50% dose of main crop fertilization and M2=sorghum stover mulch + biodecomposer 1kg/ha without NPK fertilizer. The sub-plots consisted of 2 populations: P1=population of 66,666 plants/ha (1 shoot/hole), P2=133,332 ratoon plants/ha (2 shoots per hole). The sub-sub-plots consisted of 5 (five) genotypes/varieties of sorghum: V1=Numbu, V2=No.58-1, V3=No. 86.1, V4=No.103-1 and V5=No. 113-1, so that 20 treatment combinations were obtained with 3 replications. The results showed that to obtain high grain yield in ratoon cultivation in dry land, NPK fertilization (150-100-50)/ha is still necessary. The increase in population density of ratoon from 66,666 to 133,333 plants/ha significantly affected the increase in grain yield. Sorghum genotype No. 58-1, No. 86-1, No. 103-1 and No. 113-1 is technically and economically feasible to be developed in the cultivation of the double harvest ratoon system with the profit (Rp 10,989,000-12,247,500/ha) from the cultivation of sorghum once the main crop (Rp 4,003,000-4,856,000). The R/C value is 2.00-2.10 and the MBCR value is 2.27-2.38.

Lumped Parameter Evaluation Model Analysis and Load Coupling Modeling of Piezoelectric Composite Cantilever Beam

In order to study the working mechanism of piezoelectric composite cantilever beam and improve the ability of predicting the power generation performance of piezoelectric composite cantilever vibration energy harvester (CVEH), the simple and high-precision analysis models of equivalent mass and equivalent stiffness of CVEH are proposed. The natural frequency method is used to compare the calculation results of the evaluation model, Rayleigh Ritz method and finite element simulation, and the results show that the consistency (Ω) between the evaluation model and the finite element simulation is more than 95%. The influence of the mass ratio (α) between the end mass of the beam and the weight of the beam itself on Ω is analyzed by using the proposed evaluation model, which shows that Ω increases with the increase of α, and the increase is more significant in the range of 0<α<4. The analysis of the influence of α on the natural frequency of the beam () shows that decreases with the increase of α, and the decrease is more obvious in the range of 0<α<2. According to the evaluation model, the electromechanical conversion analysis models of CVEH and its control equation with coupling of standard energy harvesting (SEH) interface circuit and Double synchronous switch harvesting (DSSH) interface circuit are established respectively, and the mathematical models of its output voltage are derived. The power generation experiment of CVEH is carried out, and the results show that the proposed models are in good agreement with the experimental results.

Biomass and methane yield of giant reed (Arundo donaxL.) as affected by single and double annual harvest

AbstractThe replacement of silage maize with giant reed as energy crop has been proposed as a mean for reducing the need of irrigation water as well as monetary and environmental costs of cultivation. Little is known about giant reed response to within‐season harvesting, and its effect on the methane production in anaerobic digestion. The effect of three harvest schedules on yield, biomass composition and methane production of giant reed was evaluated at one site of the Po Valley, northern Italy, for three consecutive years. In a completely randomized block design with four replicates the treatments applied annually were: (i) double harvest 1: first cut at the end of June + second cut at the beginning of October (DH1); (ii) double harvest 2: first cut at the end of July + second cut at the beginning of October (DH2); (iii) single harvest at the beginning of October (SH). The crop stand was established in the year 2015 and treatments were repeatedly applied in the years 2016, 2017 and 2018. The SH treatment determined the highest average annual dry matter (DM) yield (59.0 Mg DM ha−1). The DM yield for treatments with double harvest was significantly lower, that is, −30% for DH1 and −15% for DH2. In terms of specific methane yield there was little advantage in harvesting biomass twice during the growing season. The average specific methane yield varied substantially between years (i.e. from 144 to 233 ml CH4 g−1 VS), and in every year the values tended to decrease with the ageing of harvested biomass. Methane yield per hectare, however, was driven by DM yield, thus SH also determined the highest average value (9110 m3 CH4‐STP ha−1). In conclusion, the single annual harvest at the end of the growing season is an ideal strategy for maximizing methane production from giant reed.

The analysis of the elements of youth identity in the new era's main melody film and its enlightenment to the ideological and political education of colleges and universities

Under the background of globalization, the fierce ideological confrontation highlights the important value of the young audience. The new era main melody film actively self-transformation and upgrading, adjust the ideological communication strategy, through the commercialization strategy, the mainstream culture and youth culture integration, make up for the main melody film "market wing", under the support of the new media propaganda technology, accurately grasp the youth movie crowd, by the young audience's pursuit and love, harvest the word-of-mouth and box office double harvest, thus achieving the dual effect of ideological and commercial value. It also provides reference and reference for the main melody film to play its ideological and political education function.

Fiber composition and digestibility of fodder in different ryegrass fields submitted to different harvesting management systems

ABSTRACT This essay aims to evaluate the composition of fiber in neutral detergent, digestibility of plant components, as well as ruminal disappearance rate of fodder dry matter from five ryegrass fields submitted to different cut systems for the production of haylage. The experimental design was the randomized blocks one, at a 5 x 3 factorial scheme, with five cultivars (cv.) of ryegrass Lolium multiflorum (cv. Barjumbo, cv. BarHQ, cv. Ribeye, cv. Potro and cv. Willians) associated with three harvesting management systems: 1- single harvesting system at a pre-floral stage; 2 - double harvesting system, with a cut at vegetative stage and another at pre-floral stage; and 3 - triple harvesting system, with a cut at vegetative stage, a cut at full vegetative stage and a cut at pre-floral stage, with three repetitions each. Similarities were noticed on the results of fodder digestibility of different fields, however, cv. Potro presented a higher ruminal disappearance rate after 48 hours, with 69.27%. Generally, the harvesting management system with the increase of ryegrass cut frequency determined increments on the percentage of lignin and the reduction in the concentration of total nutrients and dry matter digestibility of the resulting hylage.

Remote sensing–based soil water balance for irrigation water accounting at plot and water user association management scale

Irrigation water accounting (IWA) plays a key role in irrigation management in arid or semi-arid environments. Currently, water managers perform IWA through indirect or direct measurements such as statistical methods or flow meters. However, they have a high maintenance cost and great efforts must be done when large irrigated areas must be covered. The presented framework based on the dual crop coefficient FAO56 methodology introduces an operative application of a Remote Sensing-based Soil Water Balance (RS-SWB) to obtain a Remote Sensing-based Irrigation Water Accounting (RS-IWA). A basic input of the model is the time series of basal crop coefficient and fractional vegetation cover. It has been implemented in a large water user association (100,000 ha) along three years (2010−2012). The results are analysed from the perspective of two water management scales: the plot and the water user association. At plot scale, the RS-IWA of maize and wheat, as primary crops irrigated on demand, show a root square mean error (RMSE) of about 12 % compared with the records from local farmers. At water user association management scale, the results from RS-IWA show an RMSE of about 15 % for a comprehensive range of irrigated crops group such as spring crops, summer crops, double harvest, alfalfa, and vineyards. Hence, RS-IWA based on RS-SWB offers reproducible and reliable mapped estimations that can be used for different water managers, as they are being required from actual agro-environmental laws that are pushing these actors to better knowledge in time and space of those water resources applied.

Construction of Intelligent Irrigation System for Kiwifruit Planting Base Based on PLC

With the continuous development of the intelligent water conservancy industry, it is urgently to “make up the shortcomings and strengthen the weaknesses” for the traditional water conservancy project construction. This paper takes the kiwifruit planting base in Heilin Town, Ganyu District, Lianyungang City as the control object, and uses Schneider TM221 integrated PLC module as a controller to build an intelligent irrigation system. The system uses sensors to collect data such as irrigation flow, soil moisture, meteorological information, the water level of the reservoir and water quality, and the collected data is monitored by the designed upper computer monitoring software. So that users can switch valves remotely. This system meets users’ needs for monitoring during the irrigation process, irrigation quality analysis and improvement of irrigation processes, so as to achieve automatic operation of irrigation, analysis and other processes, and achieve a double harvest of social and economic benefits.

Simultaneous two-layer harvesting of scalp split-thickness skin and dermal grafts for acute burns and postburn scar deformities.

BackgroundThe scalp, an excellent donor site for thin skin grafts, presents a limited surface but is rich in stem cells. The purpose of this study was to test a double harvesting procedure from the scalp and to evaluate the capacity of the dermal layer.MethodsTwo layers corresponding to a split-thickness skin graft (SSG) and a split-thickness dermal graft (SDG) were harvested from the scalp using a Zimmer dermatome during the same procedure. Healing of the scalp donor site, reason for recipient site grafting, and the percentage of graft loss were evaluated.ResultsFourteen patients, comprising six men and eight women with a mean age of 34.2 years, were treated according to our protocol. The most common reason for a recipient site graft was a postburn scar deformity (10/14 patients). The mean area of scalp SSGs was 151.8 cm2. The mean area of scalp SDGs was 88.2 cm2. The mean healing time of scalp donors was 9.9 days. The only donor complication was a tufted scar deformity.ConclusionsSkin defects in the scalp of donors healed faster and led to less scarring than defects at other donor sites. Scalp SDGs needed 10 days for adequate epithelization. The scalp was the best donor site for SSGs and SDGs for burn reconstructive patients.

The comparison of single and double cut harvests on biomass yield, quality and biogas production of Miscanthus × giganteus

The aim of the research was to determine the impact of double-cut harvest system on yield, as well as on suitability of Miscanthus × giganteus biomass for ensiling and biogas production. Biomass was harvested at the end of June (harvest I) and at the beginning of October (harvest II, regrowth). A single-cut regime at the end of October was also conducted. Biomass from harvests I and II was ensiled and subjected to anaerobic fermentation. The total dry matter (DM) yield from double-cut harvest system was similar to the DM yield from one-cut harvest, but two harvests per year had a positive effect on chemical composition of the biomass. C/N ratio and lignin content in the biomass from harvest I was lower compared to the single-cut biomass. Double harvest biomass was susceptible to ensiling, however, the biomass from harvest I characterized by low dry matter and water soluble sugars content resulted in poorer quality of the obtained silage (butyric acid was present). There were no significant differences between the methane yields obtained from ensiled biomass from harvests I and II.

Napiergrass Has Dual Use as Biofuel Feedstock and Animal Fodder

Core Ideas Napiergrass can produce higher biomass yield in marginal lands in the southern United States.Napiergrass can be grown as a dual source for feedstocks (bioenergy) and animal fodder.Napiergrass produces regrowth during late fall after its matured biomass harvest.Napiergrass regrowth meets the requirement for good‐quality animal fodder.Napiergrass can provide benefits to farmers following mixed crop and animal farming. Napiergrass (Pennisetum purpureum Schumach) has attracted much attention as an efficient feedstock for biofuel production in sub‐tropical climate such as the southern United States because of its perennial nature and high biomass yield, with low inputs on marginal lands. In this study, we examined if napiergrass can be harvested advantageously both for biofuel feedstock as well as fodder usage. Three harvest treatments, i.e., T1, double harvest per year, first in July (T1H1) and second in November (T1H2); T2, double harvest per year, first in October (T2H1) and second in November (T2H2); and T3, single regular harvest in November (T3), were tested for biomass yield. Plant samples from all five harvests were analyzed for quality parameters to ascertain fodder suitability. Averaged across the study period, highest dry matter annual biomass yield was recorded for T3 (41.6 Mg DM ha−1) followed by T2 (37.2 Mg DM ha−1) and T1 (35.3 Mg DM ha−1). The regrowth after October harvest (T2H2) was found suitable for fodder usage and resulted in a fresh biomass yield of 7.9 Mg ha−1 that contained 213 g kg−1 crude protein (CP), 155 g kg−1 ash, 509 g kg−1 neutral detergent fiber (NDF), and 290 g kg−1 acid detergent fiber (ADF). This study showed that napiergrass can be grown for producing biomass for biofuel production as well as a quality fodder during the late fall season in the southern United States. The results would be of special significance to farmers who follow mixed crop and animal farming.

The Method of Calculating Cut Length for Flail and Double Chop Forage Harvesters

Introduction. Many studies show that the chopped feed quality depends on the plants chopping quality. The quality of plant chopping, provided by a forage harvester, is defined by particle length distribution. It is important to find the theoretical basis of grass chopping regimes for making haylage and other kinds of feeds. The purpose of this study is to develop an algorithm and techniques to assess the quality of plant chopping based on mathematical models of chopping with the flail and double chop forage harvesters. Materials and Methods. Mathematical models of a flail type unit and double chop unit were presented and used to develop the algorithms and method of calculating the cut length distribution. Results. The algorithms and computation methods of cut length distribution were presented for a flail type unit and a double chop unit. The effect of the plant height, the height of cut, feed and the average length of cut on the mass fraction of particles within the specified ranges of lengths were investigated. Discussion and Conclusion. A flail forage harvester is not able to harvest the grass crops for making haylage with 45–75 % forage particles, the length of which is in the range from 8 mm to 19 mm. A double chop forage harvester allows harvesting the grass crops for making haylage only when auger angular velocity and/or flywheel or cylinder drum angular velocity is regulated. A double chop device can be used to chop plants for preparation of various forages if auger angular velocity and/or flywheel or cylinder drum’s angular velocity is regulated.